I have a 50L tank with 4 baby fantail goldfish (originally 3 but now Goldie lives with us because he wasn't doing too well in his first home). All fish seem well and two have grown rapidly! The other two not so well - Goldie has only just joined the gang but Lightening McQueen has a little trouble eating - his mouth isn't as big as the others and so I try and direct the smallest morsels to him.
Am feeding soaked flakes twice a day (have tried sinking pellets but they have trouble finding them), and pea snacks once or twice a day.
I have a HoB
filter and bubbles, and test the water and do a 20% PWC
every second day until I can afford a bigger tank in a month.
The tank has been running now for several weeks.
The tank has always had real plants, but I have to replace most every second week - perhaps not doing well due to lack of light?
Over those weeks I have noticed the ph continually dropping - from about 7.6 to 6.4.
Ammonia and nitrite always 0 and nitrate 40 or below.
Can't seem to work out what is happening.
I have tried researching the issue on the internet, but I trust the advice on this forum more.
I am a complete beginner, so any advice will be of great help to me